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BMI Calculator

The body mass index is one tool people use to identify risk of morbidity (disease). It is also a good indicator of total body composition (fat). In general, people with a BMI less than 18.5 or greater than 24.9 are at greater risk of morbidity. More specific ranges are provided below.

Note: These calculators require a JavaScript-enabledWeb browser to operate. Alternately, you may use the mathematical formula and explanation provided below.

BMI	Weight Status
Below 18.5	Underweight
18.5 – 24.9	Normal
25.0 – 29.9	Overweight
30.0 and Above	Obese

Calculating your BMI

The first step in calculating your body mass index, you need your weight in kilograms and height in meters. You may use the following formula to convert your weight in pounds and height in inches to the appropriate units:

Weight (lbs.) / 2.2 = Weight (kg.)

Height (in.) x 0.0254 = height (m.)

Then take these values and divide your weight in kilograms by your height twice to get your body mass index.

Weight (kg)/[height (m)]²

A BMI of less than 18.5 suggests that you are underweight and you are at risk of disease. A person is considered normal weight if their BMI is between 18.5 and 24.9. Overweight individuals have a BMI of 25 to 29.9. Individuals with a BMI of 30 or greater are considered obese. People who are obese have the greatest risk of morbidity.

The Body Mass Index may overestimate body fat in individuals who are highly muscular. It may also underestimate body fat in individuals who have lost significant muscle mass, such as the elderly.

This is a good reminder that BMI is only one piece of a person's health profile. It is important to talk with your doctor about other measures and risk factors. (e.g., waist circumference, smoking, physical activity level, and diet.)

If you are considered underweight, overweight, or obese according to the body mass index, contact your doctor to get more information about your risk of more serious disease and what specific things you can do for prevention.